Our ultimate goal is to provide a plug-and-play unified real-time communication (URTC) network in operating rooms (ORs) for image-guided therapy (IGT), where imagers, sensors, surgical robots, and computers from different vendors work cooperatively. URTC will ensure the seamless data flow among those components to enable the closed-loop process of planning, control, delivery, and feedback in IGT. The closed- loop process makes IGT interactive and adaptive, hence accurate particularly when the configuration is rapidly changing. None of existing standards truly support URTC in ORs. We are uniquely positioned to address this unmet need with our OpenIGTLink protocol; thanks to strong supports by popular free and commercial software packages, it has been used extensively in at least 89 peer-reviewed publications since 2008. Image-guidance is a basis for a wide range of minimally-invasive interventions, from percutaneous ablations to robotic surgeries. It enables accurate targeting and monitoring with minimal incisions by mapping image information onto the operating field. Image-guidance is a closed-loop process; a physician plans how to approach to a lesion using images (planning), maneuvers surgical tools to the lesion by hand or using a robotic device (control), delivers a therapeutic effect (delivery), monitors the effect using imagig and/or sensors (feedback), and update the plan accordingly. A cycle of this closed-loop process must be short enough to keep up with rapid changes in the operating field such as target displacement due to organ motion, or temperature variation during thermal ablations. Making the process closed-loop is a challenge, especially when the process involves various hardware/software components from different vendors such as imagers, surgical robots, and navigation software; those components need to communicate in real-time during the process, though there is no URTC standard suitable for the closed-loop process in IGT. Because of the lack of standard, venders can only provide proprietary communication interfaces, which are not interoperable. OpenIGTLink aims to address this unmet need in the IGT research field. It has been well accepted in the research community. However, the current OpenIGTLink puts more emphasis on the simplicity for academic research rather than the versatility required in medical-grade devices; therefore, OpenIGTLink has yet to be a de facto standard that the industry can rely on. Without the industrial support, the merit of OpenIGTLink remains somewhat limited. The goals of project are twofold: improving the protocol's advantage in real-time communication, and to improve the versatility of OpenIGTLink by providing interoperability with an existing medical record standard. We will pursue the following aims: (Aim 1) Define OpenIGTLink message exchange schemes for real-time communication with quality of service (QoS) control; (Aim 2) Investigate and develop interoperability with the DICOM standard; (Aim 3) Validate extended OpenIGTLink in a robotic system for closed-loop image-guided robot-assisted prostate interventions.